The present invention relates to an accessory, such as a probe, with internal adjustments controlled by a host, such as an oscilloscope.
Conventional testing and measuring equipment for electronic devices comprise signal acquisition accessories, such as a probe, attached to a host device, such as an oscilloscope. The host translates, displays and interprets the input from the accessory. An accessory, such as a probe, may be used for a variety of purposes and therefore preferably has variable capacities, such as threshold voltages, input coupling, bandwidth, attenuation factor, input resistance and/or capacitance.
While some accessories have set configurations, others may have several internal configurations that are switch-selectable. Some accessories store certain information, such as accessory identification and capacities, in the accessory and communicate the stored information between the accessory and the host device. U.S. Pat. No. 4,672,306, the disclosure of which is expressly incorporated herein by reference, issued on Jun. 9, 1987 to Thong, for example, describes equipping a probe with a non-volatile memory device, reading this memory from an attached oscilloscope through a serial communications interface, and conveying the information stored in the probe's memory to the oscilloscope at power-up of the oscilloscope or attachment of the probe.
Accessories, such as probes, may also have separate attachments, such as head, cable, and termination units, that must be calibrated to obtain specific measurements.
Because testing and measurement devices often measure subtle differences in an environment, accuracy of the measurement is extremely important. To increase the accuracy of the measurement, each combination of an accessory and a host device must be properly configured before it can be used. Accessories that are not properly calibrated, compensated, or otherwise appropriately configured may introduce substantial error into the measurements. Proper configuration, however, can be a complex and time-consuming process. Such complexity may derive not only from the selection process itself, but also from the need to maintain records of the information necessary to make that selection correctly.